As we learned a few weeks ago, in examining Movie Poster Booty, movie-poster design is an artform, something that takes years of dedicated instruction and practice, or at least one course at Greendale Community College taught by Senor Chang.

Indeed, marketing a movie is more than just clever taglines and 30 second trailers with 140 quick edits. It’s also about the movie poster, and next to well-placed booty, there is nothing more crucial to a successful movie poster than cleavage, or as The International Federation of Associations of Anatomists (IFAA) has termed it: Intermammary Sulcus. It’s ironic that booty and cleavage play similarly important roles, since British zoologist and ethologist Desmond Morris “theorizes that cleavage is a sexual signal that imitates the image of the cleft between the buttocks.” I’m not sure what that means, but it kind of sounds gay.

Moreover, through the ages — from the low-cut blouses of the Renaissance to the cleavage-as-a-status-symbol aristocratic era to the “delightfully tacky yet unrefined” Hooters period — cleavage has not only played an important aspect in a woman’s femininity but an equally important one in reducing a man to a blubbering simpleton, a blubbering simpleton that will pay $12 if it means seeing the crack between a woman’s breast, no matter how awful the movie.

The point is: Dudes are kinda dumb. And through decades of behavioral testing and research, those geniuses who design movie posters have been able to exploit that stupidity with the simple placement of partially covered boobs onto a movie poster. In fact, those designers have broken the art down into 12 simple categories, which I will illustrate in the slideshow that begins below.